Reviews by patients who have Tooth Pain and take Zinc either as part of daily diet or as method of treatment. Positive and negative experiences from patients with Tooth Pain that take Zinc
1 Red or black colored stool may be a sign of bleeding in the GI tract (from the esophagus, stomach, small intestine or colon) and should not be ignored.  When stool color changes, what tests need to be done depend upon depends upon what cause is suspected for the stool color change.
Certain foods can cause black stools. But if this is a consistent feature, you need to get checked. Usually black stools are caused by bleeding up higher in the GI tract. There is a bleed, the gut breaks down the red blood cells, and the iron reacts to make the black stool. This is a very very serious symptom. You need immediate assessment.